Typewriting machine



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Affar J I 5 Sheets-Sheet 1 W A DOBSON TYPEWRITING MACHINE Filed Oct. 19, 1925 Jan. 1, 1929.

Jan. 1, 1929.

w. A. DOBSON TYPEWRITING MACHINE Filed Oct. 19, 1925 3 Sheets-Sheet 2 Jan. 1, 1929. 1,696,906

w. A. DOBSON 'IYPEWRITING MACHINE Filed Oct. 19, 1925 5 Sheets-Sheet 3 Patented 1.... 1-,- 1 929.

IUNI'TED sTa'Tas PATENT OFFICE.

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r TYPEWBITING M-AQHINE.

Application filed October), 1925. Serial No. 68,870.-

ing machines, and more specifically to carriage-feedingmechanism suitable for port- -able typewriting machines. v

It 1s an ob ect in portable typewriting machines to duplicate as many of the functions performed by the more cumbersome officemachines as possible. It is an ob'ect to not only condition and lighten the mac ine struc- 10 ture for rtabilit but to'maintain a standard of esi ciency or speed that ison a par with standard typewriters. the present invention provides for the carriage-feeding mechanism that includes a minimum of operative parts to promote a maximum efliciency for speed in operation.

A portable typewriting machine should be adaptable to both, a slow and fast manipulation, and. produce uniform typing characteristics. I

The speed of the carriage-feeding mechanism primarily depends upon the ability of the carriage to move a letter-space distance between two successive type impacts without a piling up of the characters, and hence it is desirable that the let off, or the point where the carriage is released by the returning type-bar shall be as close to' the rinting position as possible. To have the "let off take place instantaneously with a type impact, would be ideal for a fast operative, but

would result in blurred characters from a slow manipulation of the keys or a sluggish type-bar-restoring action. Hence a very slight interval should be provided for after the type impact, before the let off is eflt'ective and a letter-space movement started.

.One feature of the present invention provides for a simple but eflicient means whereby a carriage-driven escapement-wheel-tooth .will pass from the control of a vibratory feeding dog to the control of a vibratory holding dog, with a slight drop in passing; theholding dog having a flat face-section to engage the tooth, and an angular or beveled face-section to quickly release the tooth. The relation of the two faces is such that the tooth, at the impact of the type, engages the flat face of the dogjust beyond the angle formed by the intersection of the said two faces, to provide for an effective interlock between the tooth and the dog, but upon the initial return movement of the dog after a type impact, the tooth will slide from the flat One object of a clearly retype light characters or make acface to the beveled face of the dog and said tooth then becomes a camming element under the carriage tension to contribute to the speed of the machine by co-operating with the typeb ar-restor1ng means. With such a construct1on a slow operative, who might allow the Qt finger to linger on the key at the end of a ke stroke, can type clear-cut impressions, whi e,

with a fast manipulation of the key, the let off is practically instantaneous to the type 1m act.

' nother feature includes a pair of escapement-dogs that vibrate in unison or independently about a common pivot mounted upon the frame. The two dogs vibrate in unison on the down stroke of the key, and at the initial return stroke thereof also move in unison to a point where the escapem entstooth engages and is actuated down the beveled face of the holding dog, camming the latter to one side. At the same time the said as capement-tooth backs off from the undercut bevel of the feeding dog until a clear passage is made between the two dogs'for the esca of the. tooth. The backing off of the stud tooth from the undercut bevel of the feeding dog restores the latter to its normal position,

.to intercept the next advancing tooth of the escapement-wheel and a letter-space movement is accomplished.

No matter how fast the carriage-feeding elements may be in themselves, an improper co-operation by the typing elements may destroy a large part of their effectiveness through the relative position of the universal bar. With the present construction the universal bar is operated b the heel of each type-bar adjacent .its pivot, and this construction operates in harmony with the present form of escapement-dogs to promote a quick let off? for the carriage-feeding elements. v I

Carriage-feeding mechanism usually includes a toothed escapement-wheel driven by a pinion in mesh with a power-driven carriage-feed rack, and to provide for a carriage-return movement, the transmission from the pinion to the escapement wheel is through a pawl-and-ratchet connection. In shifting the carriage rightward to make a correctlon, etc., it is sometimes impossible to curate letter-space connections, because of variations in these several toothed elements during the process of manufacture.

Another feature includes an escapement- I wheel that is secured to the escapement pinion as a fixed unit, to provide positive transmission between the carriage-feed rack and the escapement-whcel, and when a character is lightly typed, or a correction is to be made, the carriage may be shifted to the right to any letter sp'ace position, and a perfect registration of the type character to the former printing position will beestablished This is accomplished by arranging for a side displacement of the feeding dog, to permit the passage of the escapement-wheel-teeth in a reverse direction, by backing off of the teeth of the escapement-wheel, to cam said dog sidewise, and hence the original tooth-engagement between the rack and pinion, and the engagement of the dog with the same esoapement-wheel-too'th, prevent the displacement of any original letter-space position, due to imperfect manufacture of the several toothed elements.

Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure 1 is a vertical, longitudinal section through a ortable typewriting machine, with some of the parts omitted.

Figure 2 is an enlarged view, in perspective, of the escapement-wheel, showing the method of backing off the side face of each tooth.

Figure 3 is a detail plan view of the universal bar, escapement-wheel and escapement-dogs in normal inoperative positions. V

Figure 4 is a skeleton view, in perspective, showing a novel universal-bar construction and connections.

Figure 5 is a front elevation of the carriage-feeding devices with the front section of the machine removed.

Figure 6 is an enlarged view of the escapement-pinion and wheel, showing one tooth of the wheel in normal operative relation to the two escapement-dogs.

Figure 7 is an enlarged plan view of the carriage-feeding elements with the escapement-wheel and dogs in normal position.

Figure 8 is a view, similar to Figure 7, except that the dogs have been vibrated to a position timed to the impact of the type against the platen.

Figure 9 is an enlarged View of the typebar that has made an impression against the platen and returned to the position shown where the engaging tooth of the escapementwheel is about to engage with the beveled face of the dog.

Figure 10 is an enlarged view, showing the tooth of the escapement-wheel moved from the position of Figure 9, and free of the control of the beveled face of the holding dog, after pushing the feeding dog to one side to enable the tooth to pass between the two dogs to effect a letter-space movement of the carriage.

Figure 11 is a view similar to Figure 8, showlng the same relation of the parts as at Figure 10. v

Figure12showsth riage-feeding mechanism shifted to uppercase position, and the relation of the shifted parts to the universal-bar connection and also to the connection of the space-bar.

This portable machine has a keyboard arranged in four banks of keys, including numeral-keys 20, alphabet-keys 21 and aspacebar 22. The keys and 21 operate key-levers 21 held in parallel vertical planes by a comb-plate 23 at the front of the machine, and fulcrumed at their rear ends on a rod 24. The key-levers held are under tension in normal position by individual springs 24. Each key-lever 21 is provided with a stud 25 and engages within a slot 26on one arm of a bellcrank 27 fulcrumed upon a wire 28 and spaced within slots in a cross-bar 29 to properly align them with the key-levers. opposite arm of each bell-crank 27 rises above the key-levers 21 where the ends have a connection 30 to a short arm 31 of typebars 32, fulcrumed upon a wire 35 and assembled within slots in a segment 36 to guide the movement of said bars from the pad 37 to the platen 38 at each stroke of a key 20 or 21.

The segment 36 may be secured to side frames 39 of the machine in any suitable man- The e carriage-platen and carner and pitched rearwardly fromthe vertical,

so that a type-bar after leaving the pad moves upwardly, rearwardly and downwardly to a visible printing position on the platen. The platen 38 is rotatablymounted within end plates 40 of the carriage-truck, which includes a bar 41 to which the two carriage ends 40 are secured. The bar 41 at each longitudinal edge may be formed with raceways 42 which co-operate with front and rear raceways 43 and 44, respectively, which form a part of a shifting frame 45 operated by means, not shown, to shift the platen and carriage-truck in a plane parallel to the plane of the segment for a case-shift position. The carriage is urged towards the left end by a suitable spring-drum 46 connected by a tape 46 to a carriage-endplate 40 in the usual manner.

The carriageefeeding elements include a rack 47 secured at each end to a crank-arm 48 pivotally mounted upon a screw 49 at each carriage end 40. One or both of the carriage ends may be provided with a carriage-release lever 50 fulcrumed upon a platen-shaft 51 with one arm engaging the crank-arm 48, and another arm terminating in a finger-piece 52. The lever 50 may be provided with a spring 53 to restore the feed-rack 47 to a normal operative position determined by a stop-arm 54 engaging the end plate 40.

The carriage-feed rack 47 meshes with a pinion 55 rotatably mounted on a shoulder- IOU tion therewith by a screw 56". Asthe rack -17 is maintained in operative engagement with the'pinion 55 by the spring 53, it is a desirable assembling and adjusting feature to avoid any grind between these two tooth elements from excess spring tension. The stop-arm 54 on the lever may be bent either up or down, and, in this manner, a simple adjustment is provided to condition the feedrack 47 so that the teeth thereof may engage properly with the pinion and with only a working tension between the teeth to promote a silent transmission. A carriage-releasing movement of the rack by the fingerpiece 52 may be limited by an adjustable stop 41.

An escapement-wheel 58 and the pinion 55 are rotata le upon the stud 56 as a unit, and to effect letter-space movements of the carriage a pair of escapement-dogs 59 and are vibrated to co-operate with teeth of the escapement-wheel. These two dogs may be described as a feeding dog and a holding dog. The dog 59, though normally a holding dog, effects the escape or feeding of a tooth of the wheel 58 at each return vibration thereof, and will hereinafter be termed a feeding dog, and the dog 60 that temporarily holds the same tooth to prevent rotation of the wheel until the feeding dog 59 is conditioned to effect or promote a letter-space movement will be termed a holding dog. In the present construction each of the two dogs 59 and 60 forms a part of a dog-rocker 61 and 62 formed with ears 63 and 64, respectively, which nest together to vibrate about a common pivot 65 carried by ears 66 projecting from a plate 67 secured to the back plate 57 of the shiftframe 45. The relation of these parts provides that cars 64 of the rocker 62 may nest within the two cars 66 of the plate 67, and the two cars 63 of the rocker 61 may nest within the two ears 64, which arrangement provides for a compact close-fitting construction with a single pivot for both rockers 61 and 62.

The two dogs 59 and 60 lie in parallel planes with a separating gap 68 between them which is less in width than the width of the face of the escapement-tooth. This gap 68 is maintained by a stop-lug 69 on the dog 59 to abut the dog 60 under expansion of aspring 70; the dog 59 being spring-pressed towards the dog 60 provides that both dogs will vibrate about the pivot-screw 65 as a unit. To maintain the two dogs 59 and 60 in normal operative position relative to the escapement-teeth, the section 62 may be provided with an adjustable stop-screw 71 threaded through the plate 67 with the free end thereof engaging with the face of said rocker 62 under tension of a compression spring 72 bearing against the rocker on the 'face of the holding dog opposite side of the pivot 65. The tension 0 said spring 72 may be made variable by the adjustment of a screw 73 to give the dogs a quic r snappy restoring movement to effect the escapement of a tooth of the escapementwheel.

It will be noted at this point that when the several. parts are positioned, as at Figures 6 and 7, with the two dogs 59 and 60 vibrating rearwardly as a unit and in a manner resently to be described, the movement of the dog 60 compresses the spring 72 which forces the feeding dog 59 to sideslip from the face of, and abut the side of, a tooth 58 of the .escapement-wheel 58. The latter with a very slight drop will rest upon the faceof the holding dog 60, and at the end of the rearward movement the parts will assume the positions of Figures 8 and 9. The tooth 58 on leaving the dog 59 overspans the gap 68 separating the two'dogs, because the face of the tooth is wider than the width of the gap, and the tooth also overspans a beveled face 60 of the dog 60, so that the edge of said tooth may rest upon the flat top of the dog. In this position, which is timed with the impact of the type at the platen, the tooth is held by induced pressure against the flat top of the dog 60 which prevents a letter-space movement, but when the restoring action of the spring 72 is released, as by the return movement of a type-bar to the position of Figure 9, the fiat top of the dog 60 sideslips from the face of tooth 58, and leaves the latter free to advance onto the beveled face 60. The carriage-tension actuating the tooth 58 forces the latter down the beveled face 60, thus effecting a camming action, which assists the spring 72 to restore the dog 60 in the direction towards its normal position against the stop 71.

To effect a letter-space movement, the tooth 58 by its thrust on the bevel 60 forces the holding dog 60 far enough to one side to permit the passage of tooth 58 through gap 68, as at Figures 10 and'11.-

It will be noted that the dog 59 has an undercut face 59, and that each tooth on the side adjacent the dog 59 is backed off, as at 58", and hence when the tooth 58 passes between the two dogs 59 and 60, the under-cut face 59" of the dog and the backed-off side face of the tooth permit the dog 59 by the expansion of its spring 70 to move towards the dog 60 and assume a position to positively intercept the next advancing tooth 58 of the wheel 58.

When the feeding dog 59 slides outward from under the tooth 58, but without leaving the same, the tooth drops onto the top 60. If said tooth dropped onto the beveled face 60 instead of the top face of the holding dog 60, the carriage-feeding mechanism would be unsuitable for the average operative, because of released to assume the position of theluniversal bar at r1 variable letter-spacing promoted thereby.

It is the purpose of this inventionto so the operative parts that the engaging tooth of the esca ement-wheel shall just overlap the beveled ace and rest upon the flat face of the dog to effectively prevent a letter-space movement'to take place until the ty e-bar is igure 9; which provides for a maximum interval for the carriage toesca between impacts, prevents skittering of t e carriage under a slowof the se ment 36, sai bar is secured at ears 77 to a vibratory frame 7 8 suspended at the forward end by a tongue 79 secured thereto whichenters a. slot in the segment. The rear end of theframe 78-ma be suspended by suitable links 80 pivote to the frame and positioned to 've said frame 78 approximately a straig it-line to-and-fro movement. The frame 7 8, as a whole, may be urged forwardly, until checked bythe universal bar engaging the segment 36, by aspring 78 secured between said frame and a bracket 7 8'? rising from a cross-bar 95. To the frame 78 may be secured a suitable abutment 81 to engage with a screw 82 that extends from a oint at the rear of the back plate 57 throw the plate 67, threaded through the dog-rocker 62 and provided with a check-nut 83 to hold any adjusted position of the screw.

When a type-bar is thrown to the position of A, Figure 1, the heel 76 of the bar will engage with the universal bar'75, and from this point A to the printing position the typebar will vibrate the universal bar and frame 78, but as this transmitted type-bar movement is an excess of what is required to operate the escapement-dogs, said frame 7 8 may be given a short, free, rearward movement before the abutment 81 is brought into engagement with the screw 82 to vibrate the dog-rockers 61 and 62. This inactive interval may be increased or diminished through the adjustment of the screw 82 to predetermine the degree .of overlap for an escapement-tooth relative to the plate face of the holding dog 60, and incidentally predetermine the position for the carriage-feeding let-off during the return movement of the type-bar:

The carriagefeed mechanism, as described, is operated by the keys 20 or 21, and the universal bar usually operates the ribbon-v1- brator, as well as effects a letter-space movement of the carriage, and it is a desirable feature to have an independent connection from the space-bar 22 to the escapement mechaht angles to the plane.

. tooth of the escapement-wheel.

nism to avoid vibrating the ribbon-carrier unnecessarily each time the space-bar is depressed. As shown at Fi res 1 and 4, the s ace-bar is positioned in rent of and below t e lowest bank of keys 21 and suspended upon the front ends of two arms 84 secured at' the rear ends to a rock-shaft 85 mounted wlthin bearing-earSlSG-forming part of the front comb 23. The bar 22 may have a suitable spring 87 to hold it in a raised position determined by a stop-arm 88 engagable with astop pad 89 on the frame, and said pad may also limit the down stroke of said bar 22. The rock-shaft 85 has an upright crank-arm 90 secured thereto, with the end pivotally connected to a link 91 that extends rearwardly to a point adjacent and under the escapement mechanism where it is formed with an upright arm 92, that rises above, but adjacent to, the free end 62 ofthe rocker 62, that carries the holdin dog 60. The rear end of the link 91 may e suspended, by a pin-and-slot-connection 93, from the upper end of a bracket 94 secured to the crossbar 95. v

The present dog 59 does never slip by any On the contrary, the escapement-wheel tooth slips past the dog 59, while the dog 59 is sinking mto a notch of the wheel, whereb the dog 59 reaches the point where it is in the'path of the next tooth. This possibility of having a nonvibrating dog 59 occurs, because the wheel 58 begins to slip as soon as it is released from the dog 59, Figure 10. Such initial step of the escapement-wheel, however, is very slight. But it is enough to enable the released wheeltooth to take up a position in the path of the returning dog 59, to obstruct the dog 59 temporarily, and allow the dog to sink in (by the force of sprin as the escapement-wheel advances, so t at dog 59 is sure to intercept the next tooth of the escapement-wheel and arrest the same. The spring 70 permits the dog 59 to be temporarily arrested (by striking .facewise a ainst the face of the released wheel-tooth? while the dog 60 completes its stroke. l

, Referring to Figures 1 and 12, it will be noted that the complete carriage-feeding mechanism is mounted upon the case-shift frame 45, and as the abutment 81 and the arm 92 are stationary with the frame of the machine, both these members 81 and 92 have an operative height to en age their respective co-acting parts 82 and 62 at both caseshift positions of the carriage.

To remove some of the noisy clicking from the escapement dogs, especially the feeding dog 59, aflat spring 96 may be riveted to the face of the holding dog-rocker at 97 with the free end extending to a position against the stop-lug 69, which spring 96 by its own tension acts to separate the two dogs 59 and 60, but is restrained from doing so by the heavier tension of the sprin controllin the restoring movement of the dog 59. en the operative tooth of the escapement-wheel causes a side-stepping movement of the dog 59 to permit the passage of the tooth between the two dogs, the dog 59, as already described, is spring-pressed to force said dog to follow the incline of backed-off face of the tooth, and assume its normal position to engage the next advancing tooth of the wheel. When the operative tooth drops from the dog 59, said dog will naturally ress toward 1ts normal position nearer the 0g 60 by the tension of the spring 70. The s ring 96, which 1s under tension, acts throug the lug 69, on the dog 59 as shown at Figure 11, to partially retard the action of the spring 70, wlth the result that the noise developed by the restoring movement of the dog 59 will be a thud instead of a. click, and not be so noticeable as a noisy element in the carriage-feeding mechanism.

It will be seen that springs 70, 72 and 96 form a means for automatically taking up any wear between dogs 59 and 60 and their pivot 65, so the dogs remain operative. Dog 60 has a long arm 62 which gives a bi levera at 62, and thus makes easier the vi ration of the two dogs by the space-bar 22 and its arm 92. The escapement-tooth by its camming action on dog 60 tends throu h the opposite end 62 to restore the spacear mechanism to normal sition. The escapementtooth b its cammmg action on dog 60, acting throug the abutment 81, tends to restore universal bar to normal position, thus aiding in the quicker restoration to normal position of the type-bars 32. The long arms of dog-rockers 61 and 62 afford an increased leverage at points of contact of the springs 70 and 72. Said springs therefore can have little tension, with a resultant lessened pressure of the dogs 59 and 60 against the escapement-wheel. This reduces wear between said dogs and saidwheel, and gives these three elements a longer operative life. Dog-rockers 61 and 62 ma have a spring 96 between the same, whic by its retarding action, may tend to reduce the noise that would result should lug 69 or rocker 61 directly strike the rocker 62 without the cushioning effect of spring 96. Ina back-spacing movement, the same identical tooth maintains a former let-- tor-space position, so type imprints exactly where it would in said former letter-space position. It will be seen that minimum arts secure maximum efficiency, and that Functions of standard size machines are performed. The carriage let-off occurs close to printing position, allowin a slight interval or slow operators. The og by a camming action helps restore the type-bar to normal, and the s11 ht drop permits the wheel to ass from the eeding to the holding dog. he escapement-whee is fixed to the pinion;

ratchet and pawl being eliminated. The relocation of letter-space 1n back-spacing is positive, as the same tooth is used. The dogs are extremely compact, simple, cheap and ight.

Variations may be resorted to within the scope of the invention, and portions of the im rovements may be used without others.

hold the same tooth for a typing operation and condition the tooth to effect a side steping of the feeding do to release the tooth rom the holding dog r the typing operation, a key-actuated universal bar to operate the dogs in typing, and a space-bar connection slidably mounted upon the machineframe to operate the dogs independently of the universal bar and at either shift position of the carriage.

2. In a typewriting machine including a frame, the combination of a carriage, having a feed-rack movable therewith, and rackfeeding mechanism mounted upon the frame and co-operative with said rack including a pair of dog-rockers having spaced-off ears to provide long bearings for both rockers, the ears of one rocker nesting within the ears of the other rocker to individually rock about the same fulcrum and each rocker having a single dog, both dogs cooperative to effect the feeding movement of the rack.

3. In a. typewriting machine having a spring-driven carriage, a carriage-rack and an escapement-wheel, the combination of an inflexible feeding dog 59 normally holding the wheel against rotation, a detent-dog 60 operable by the keys to push the feeding do out from the wheel, said dogs being mounte upon one pivot, the axis of said pivot being parallel to the face of the escapemenhwheel, said detent-dog having a drop 60 against which the tooth of the released escapementwheel slightly advances or drops, and by which the escapement-wheel is temporarily arrested and held stationary, together with the carriage, while the feeding dog 59 is maintained in released position by the depressed finger-key, a spring 72 for restoring dog 60 when the finger-key is released, thereby permitting advance of the wheel one tooth, and a spring70 tending to urge the feeding dog 59 to move in the same direction as the detentdog 60, notwithstanding that said dog 59 is intercepted by striking against the face of the wheel-tooth which has just been released and is restrained thereb while the dog 60 is being returned by the spring 72.

f hence to interce t the esce carriige.

5. echanism according to claim 3 having a. shift-frame for the carri e on which the eecapement is mounted, an having a keydriven actuetor 81 of suflicientheighlt to 01}- erate the dogs at all up-and-down s ft-positions of the escapement-wheel, dogs and typewriter-carria track-frame.

6. Mechanism according 'to claim 3, having a lever 92 operated by a space-key 22 and enggfiieable with arm 62" of the do 60, and of cient height to operate said 0g at all up-and-down shift-positions of the carriagetrack-frame.

WILLIAM A. noisson. 

